+ p1.x=x1; p1.y=y1;
+ p2.x=x2; p2.y=y2;
+ p3.x=x3; p3.y=y3;
+ p4.x=x4; p4.y=y4;
+
+ {p1.x = (int)(p1.x*20)/20.0;
+ p1.y = (int)(p1.y*20)/20.0;
+ p2.x = (int)(p2.x*20)/20.0;
+ p2.y = (int)(p2.y*20)/20.0;
+ p3.x = (int)(p3.x*20)/20.0;
+ p3.y = (int)(p3.y*20)/20.0;
+ p4.x = (int)(p4.x*20)/20.0;
+ p4.y = (int)(p4.y*20)/20.0;}